Things I liked:After my first tin of these pellets with my gen 1 marauder I was hooked. The tin has a foam pad on the bottom and one on the top of all of the pellets to keep them from moving around. And after taking calipers to about 50 pellets and they all measured out to be 5.51mm, I am confident these pellets are all pretty close to 5.51mm. Things I would have changed:I don't know if there is much of anything I would change. I know these suckers get sold out for a while so maybe a quicker restock time? But I think they may be imported, so delay is all part of the import game. What others should know:For my gen 1 marauder I have tried all walks of the JSB .22 pellets and almost any round nosed pellet sold by Pyramydair to include the copper ones, and these AirArms 5.51mm 16 gr pellets group the best. I keep nickel sized groups at 30 yards. With the best JSB's I could group no smaller then a quarter at 30 yards. This is true even with my second Marauder barrel purchased form Crosman. So maybe it's my luck or these pellets are one of the better pellets to use.